There has been a conventional practice to provide advertisement using media such as television and radio broadcasting. The advertisement using television and radio broadcasting allocates time intervals for the advertisement between programs and between time-shared portions of a program. A broadcast signal for the advertisement is transmitted during the allocated time (the National Association of Commercial Broadcasters in Japan, ed. Broadcasting handbook—Practical knowledge about the civil law as a culture background: TOYO KEIZAI INC., August 1997, pp. 340-343).